Whole blood is made up of various cellular and non-cellular components such as red cells, white cells and platelets suspended in its liquid component, plasma. Whole blood can be separated into its constituent components (cellular, liquid or other), and the separated component can be administered to a patient in need of that particular component.
The administration of blood and/or blood components is common in the treatment of patients suffering from disease. Rather than infuse whole blood, it is more typical that individual components be administered to the patient(s) as their needs require. For example, administration (infusion) of platelets is often prescribed for cancer patients whose ability to make platelets has been compromised by chemotherapy. Infusion of white blood cells (i.e., mononuclear cells), after the cells have undergone some additional processing or treatment, may also be prescribed for therapeutic reasons including treatment of diseases that specifically involve the white blood cells. Thus, it is often desirable to separate and collect the desired blood component from whole blood and then treat the patient with the specific blood component. The remaining components may be returned to the donor or retained for other uses.
There are several diseases or disorders which are believed to primarily involve mononuclear cells, such as cutaneous T-cell lymphoma, organ allograft rejection after transplantation and autoimmune diseases such as rheumatoid arthritis, systemic sclerosis, among others.
Cutaneous T-cell lymphoma (CTCL) is a term that is used to describe a wide variety of disorders. Generally, CTCL is a type of cancer of the immune system where T-cells (a type of mononuclear cell) mutate or grow in an uncontrolled way, migrate to the skin and form itchy, scaly plaques or patches. More advanced stages of the disease also affect the lymph nodes. Therapeutic treatment options for CTCL have previously been limited. While chemotherapy has been utilized, this particular form of treatment also has many associated undesirable side effects, such as lowered resistance to infection, bleeding, bruising, nausea, infertility and hair loss, just to name a few.
Organ allograft rejection may be characterized as the rejection of tissues that are foreign to a host, including transplanted cardiac tissue as well as lung, liver and renal transplants. Immunosuppression drug therapy following transplantation is common. However, there are potential drawbacks including reoccurring infection due to the compromised competence of the immune system caused by this type of therapy.
Similarly, graft versus host disease (GVHD) is a complication that can occur after a stem cell or bone marrow transplant in which the newly transplanted material attacks the transplant recipient's body. The differences between the donor's cells and recipient's tissues often cause T-cells from the donor to recognize the recipient's body tissues as foreign, thereby causing the newly transplanted cells to attack the recipient. GVHD may complicate stem cell or bone marrow transplantation, thereby potentially limiting these life-saving therapies. Therefore, after a transplant, the recipient is usually administered a drug that suppresses the immune system, which helps reduce the chances or severity of GVHD. See Dugdale, David C., et al. “Graft-Versus-Host Disease,” MedlinePlus A.D.A.M Medical Encyclopedia, Updated Jun. 2, 2010.
Autoimmune diseases, including rheumatoid arthritis (RA) and progressive systemic sclerosis (PSS), can be characterized by an overactive immune system which mistakes the body's own tissues as being a foreign substance. As a result, the body makes autoantibodies that attack normal cells and tissues. At the same time, regulatory T-cells, which normally function to regulate the immune system and suppress excessive reactions or autoimmunity, fail in this capacity. This may lead to among other things, joint destruction in RA and inflammation of the connective tissue in PSS.
Where existing therapies for treating one or more diseases may result in certain unintended side effects, additional treatment may be desired or required. One known procedure which has been shown to be effective in the treatment of diseases and/or the side effects of existing therapies involving mononuclear cells is extracorporeal photopheresis or “ECP”. Extracorporeal photopheresis (also sometimes referred to as extracorporeal photochemotherapy) is a process that includes: (1) collection of mononuclear cells (MNC) from a patient, (2) photoactivation treatment of the collected MNC cells; and (3) reinfusion of the treated cells (MNC) back to the patient. More specifically, ECP involves the extracorporeal exposure of peripheral blood mononuclear cells combined with a photoactive compound, such as 8-methoxypsoralen or “8-MOP” which is then photoactivated by ultraviolet light, followed by the reinfusion of the treated mononuclear cells. It is believed that the combination of 8-MOP and UV radiation causes apoptosis or programmed cell death of ECP-treated T-cells.
Although the precise mechanism of action in ECP treatment (in the different disease states) is not fully known, according to early theories, it was believed that photoactivation causes 8-MOP to irreversibly covalently bind to the DNA strands contained in the T-cell nucleus. When the photochemically damaged T-cells are reinfused, cytotoxic effects are induced. For example, a cytotoxic T-cell or “CD8+ cell” releases cytotoxins when exposed to infected or damaged cells or otherwise attacks cells carrying certain foreign or abnormal molecules on their surfaces. The cytotoxins target the damaged cell's membrane and enter the target cell, which eventually leads to apoptosis or programmed cell death of the targeted cell. In other words, after the treated mononuclear cells are returned to the body, the immune system recognizes the dying abnormal cells and begins to produce healthy lymphocytes (T-cells) to fight against those cells.
In addition to the above, it has also been theorized that extracorporeal photopheresis also induces monocytes (a type of mononuclear cell) to differentiate into dendritic cells capable of phagocytosing and processing the apoptotic T-cell antigens. When these activated dendritic cells are re-infused into systemic circulation, they may cause a systemic cytotoxic CD8+ T-lymphocyte-mediated immune response to the processed apoptotic T-cell antigens like that described above. It will be appreciated that other possible mechanisms of action may be involved in achieving the benefits that have been observed from the ECP treatment of mononuclear cells and the subsequent benefits to patients undergoing ECP based therapies.
More recently, it has been postulated that ECP may result in an immune tolerant response in the patient. For example, in the case of graft versus-host disease, the infusion of apoptotic cells may stimulate regulatory T-cell generation, inhibit inflammatory cytokine production, cause the deletion of effective T-cells and result in other responses. See Peritt, “Potential Mechanisms of Photopheresis in Hematopoietic Stem Cell Transplantation,” Biology of Blood and Marrow Transplantation 12:7-12 (2006). While presently the theory of an immune tolerant response appears to be among the leading explanations, there exist other theories as to the mechanism of action of ECP relative to graft-versus-host disease, as well as other disease states.
Systems for performing ECP include, for example, the UVAR XTS Photopheresis System available from Therakos, Inc., of Exton, Pa. Further details of performing ECP on the Therakos system can be found, for example, in U.S. Pat. No. 5,984,887.
While the clinical benefits of ECP have been recognized, the use of ECP is not without its own drawbacks, including the systems and methods by which the ECP treatment is performed. For example, there are currently two commonly used methods for performing photopheresis—online and offline methods. In online methods, a dedicated photopheresis device, such as the Therakos device mentioned above, is used to perform the entire therapy including reinfusion of treated MNCs. Such devices are “dedicated” photopheresis devices, designed only for performing photopheresis and cannot perform other collection protocols needed in a hospital or blood processing setting including, for example, multifunctional apheresis protocols for collection of platelets, plasma, RBCs, granulocytes and/or perform plasma/RBC exchange protocols. In offline photopheresis methods, a multifunctional apheresis device may be used to collect mononuclear cells. The collected MNCs, typically contained in one or more collection containers, are severed or otherwise separated from the tubing set used during collection, where they are later treated in a separate irradiation or UVA light device followed by manual reinfusion of the treated cells to a patient. However, during such offline methods, when the cells are transferred from the apheresis device to the irradiation device (which device may be located in another room or laboratory) communication with the donor must be severed and accordingly, the cells detached from the donor. Thus, additional traceability procedures are required to insure that the treated MNC product is ultimately reinfused into the correct donor.
Therefore, it would also be desirable to develop “on line” systems and methods for providing ECP-treated mononuclear cells which avoids any additional product labeling and/or traceable handling requirements because the MNC product never leaves the disposable set which remains connected to the donor during the entire ECP treatment procedure. To this end, the systems and methods described herein include (1) a multifunctional automated apheresis device for harvesting MNCs from whole blood and reinfusing treated MNCs to a patient, (2) an irradiation device housed separately from the apheresis device which irradiates MNCs combined with 8-MOP to obtain treated MNC and (3) a disposable set which proves a sterile, closed pathway between the apheresis device and irradiation device and which remains connected to the patient during an entire photopheresis procedure. Use of a multifunctional apheresis device in accordance with the systems and methods described herein allows a hospital or medical facility to procure and maintain fewer apheresis devices, taking up less space and being more economical than having to acquire dedicated photopheresis devices used solely for performing ECP treatment, while also retaining a sterile closed pathway between two separate processing devices.